Here is a game my wife and I came up with to add a little fun to masturbation. It can be used with either self-masturbation or one person masturbating the other person. Linda likes me to stand and "perform" in front of her and this game has added an interesting twist to it.
Feel free to tweak it as you like...
Using a regular deck of cards with jokers included (optional), someone (can be either person) selects one card. This card will establish the length of time the masturbator is allowed to perform. The ‘goal’ is to reach climax within the allowed timeframe.
Ace: 1 minute
Two thru ten: 2 minutes, 3 minutes, 4 minutes, etc. to 10 minutes
Jack: 11 minutes
Queen: 12 minutes
King: 13 minutes
Joker: as much time as needed
Option: Game ends when climax is reached unless if a red suited card is drawn, then the masturbator must stop at the end of the allowed time. If a black suited card is drawn then the self-masturbator may continue alone until climax is reached but the other person(s) will leave at the end of the allowed time.